JP2902174B2 - Gait control method for mobile robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gait control method for a mobile robot.

[0002]

2. Description of the Related Art Conventional crawling gait control is shown in FIGS.
In the form shown in FIG. 5, the movement of an uneven portion whose shape and dimensions are known in a known environment has been considered. For this reason, the gait moves in accordance with a previously created gait pattern, and correction by the sensor is limited to a delicate correction operation. FIG. 14 is a step crossing pattern, and FIG. 15 is a convex crossing pattern. In the figure, reference numerals 13 and 14 denote moving objects, 7 denotes a right front leg, 9 denotes a right rear leg, and 12 denotes a right driving wheel. (Japanese Patent Application No. 60-
163877 and Japanese Patent Application No. 2-248181)

[0003]

The creation of a gait pattern off-line based on moving environment data requires a lot of time and effort, and moving in an unknown environment (outdoor or the like) is almost impossible. Was.

[0004]

A method of controlling a gait of a crawling mobile robot according to the present invention for solving the above-mentioned problems is to provide a robot body having a plurality of articulated legs and a grounding of the robot body. A grounding sensor for detecting is provided on the robot body, and a grounding sensor for detecting that the leg is in contact with the leg is provided on the leg. The legged mobile robot mounted on the main body and the legs or the robot main body or the legs lifts the free leg operation in which each leg moves with the robot main body grounded, and each leg supports the robot main body with each leg grounded In a crawling mobile robot that moves in a crawling manner by repeating a standing leg movement, the legs can stably touch the ground during the free leg movement and are farthest in the traveling direction. After moving and touching the place, the robot body can be stably grounded while standing up and moving and touching the farthest place in the direction of travel. It is characterized by automatically generating a gait of a crawling movement without creating it.

[0005]

[Function] The leg or robot body can be stably grounded in the traveling direction by the free leg operation and the standing leg operation, and the operation of touching the ground as far as possible within the movable range of the leg or the robot body can be repeated. Achieve movement without changing.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A leg-wheel type mobile robot for carrying out the method of the present invention will be described with reference to FIG.

[0007] This leg-wheeled mobile robot will be described.
The mobile robot body 1 is provided with a pair of driving wheels 2 (only one is shown in the figure), a pair of front legs 3 and 7, and a pair of rear legs 5 (only one is shown in the figure). A wheel 4 is attached to a tip of the left rear leg 5 and a wheel 6 is attached to a tip of the left rear leg 5. The left front leg 3 is a two-joint type leg having a right thigh 3b, a left thigh 3d, a hip joint 3a, and a knee joint 3c, and each joint 3a, 3c is provided with a drive mechanism and an angle detector. Similarly, the left hind leg 5 is a two-joint type having an upper leg 5b, a lower leg 5d, a hip joint 5a, and a knee joint 5c, and each joint 5a, 5c is provided with a drive mechanism and an angle detector. Each of the wheels 4, 6 at the tip of the leg is provided with a brake, a drive mechanism, and an angle detector, and can independently rotate as a drive wheel. However, when the brake is released and there is no drive force, an external force is applied. It rotates and becomes a driven wheel.

Each of the wheels 4, 6, 8 (the right rear wheel is not visible in the figure) and the left driving wheel 2 (the right driving wheel is not visible in the figure) are equipped with force sensors, and are in contact with the moving object. Is detected.

FIGS. 4 and 5 show examples of the external sensor at the leg tip. FIGS. 4 and 5 show the sensor of the left front leg, and the ultrasonic sensor 10 is connected to the wheel 4 at the tip of the lower leg 3d and rotates. The sensor main body 10a is provided with an ultrasonic oscillator 10b and an ultrasonic receiver 10c. The ultrasonic wave 10d is oscillated from the ultrasonic oscillator 10b, reflected by the moving object 11 and returned to the ultrasonic receiver 10c, and the distance between the ultrasonic sensor 10 and the object can be determined from the time from oscillation to reception. Actually, the distance l ₀ between the wheel 4 and the ultrasonic sensor 10 is determined from the distance l _m between the ultrasonic sensor 10 and the moving object 11.
The l _r is the distance between the mobile object 11 and the wheel 4 minus.

Here, an example of a sensor using an ultrasonic wave has been described, but it is also possible to use an optical sensor, a visual recognition sensor, or a mechanical sensor using a limit switch or the like.

The control method of the present invention will be described.

FIG. 6 is a schematic flow chart showing one cycle of the crawling movement of the four-legged robot shown in FIG. After performing the free leg motion two legs at a time and replacing the tip of the leg forward in the traveling direction, the main body is moved forward by the standing motion to move one step. It is possible to move by repeating this process.

FIG. 7 is a flowchart in which the movement of the legs and the main body in FIG. 6 is further disassembled. Lift the leg or the main body and move it in the traveling direction as much as possible so as not to interfere with the moving object (the detailed procedure is shown in FIG. 8).
Grounding where stable grounding is possible (detailed procedures are shown in FIGS. 9 and 10).

FIG. 8 shows a flow chart of the movement of the leg or the robot body in the traveling direction in FIG.
The robot body moves so as not to interfere with the moving object while sensing the outside world with the sensors shown in FIGS.

FIGS. 9 and 10 are flow charts for stably grounding in FIG. In the operation shown in FIG. 8, if the landing is possible at a place where the leg is moved in the traveling direction as much as possible, the leg or the robot body is directly grounded. If the location is unstable, search for a place where the ground can be reached, and then retract the leg or the robot body. If a suitable place is found, ground the robot.

FIG. 13 shows a situation for grounding the legs as far as possible. Farthest ground point which can be grounded for Ashisaki a radius R _max and the intersection P _max and the ground plane _{P max (x max, y max} ) , however, interference between the legs and the ground occurs in this state. Therefore, P ₂ (x ₂ , y ₀ ) toward P _max → 0 (x ₀ , y ₀ )
₂ ) Go and

[0017]

(Equation 1)

By solving Equation 1, the intersection P₁(X₁, Y₁)
Ask. Straight line OP₁, P₁P_TwoAnd whether it does not interfere with the ground
Check (OP₁, P₁P _TwoThere are no ground coordinates on top
When). P that satisfies₁Is within the movable angle of the leg
Check whether or not. θ_1min<Θ₁<Θ_1max θ_2min<Θ_Two<Θ_2max If is satisfied, it will be a ground point. P_TwoBased on_TwoSearch for neighbors and find
Correct the input ground error and ground. However, the limit is actually sufficient to absorb the error of
With enough margin. Legs can be made by the above method
Just ground it far away.

FIG. 11 shows the condition of the movable range of the leg. _Find a contact point P (x ₂ , y ₂ ) between x _max and the ground, and
_{If min} <y ₂ <y _max , the interference with the leg is checked by the above procedure. If there is interference, move in the direction of x _max → x _min and repeat the same.

FIG. 12 shows an example of the free leg operation when the movable range of the leg is as shown in FIG. The right front leg 7 at point a is lifted and moved forward. When it interferes with the moving object 11, it moves upward to a place where it does not interfere, and when it reaches a height that does not interfere, it moves forward again. Eventually, the operation goes to the limit b of the movable range and stops. Then, a grounding operation is performed. If there is no place where the ground can be stably grounded, the right front leg 7 is returned while searching for it. .

FIGS. 1 and 2 show the movement of the legs when the vehicle climbs over a step according to the method of the present invention. FIG. 2 shows the plane state of FIG. By repeating these operations, it is possible to move around without patterning.

According to the present invention, even when the shape of the ground is unknown, the tip of the leg can be moved to the minimum movable range side in the x and y directions to search for a ground contact point.

[0023]

According to the method of controlling a gait of a crawling mobile robot of the present invention, it is not necessary to create a gait pattern in advance based on a moving object (moving environment), and it is not possible with a patterned gait. Can be moved. As a result, it is not necessary to measure and investigate the moving object in advance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an operation of moving over a step by a control method according to an embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a perspective view illustrating an appearance of a leg-wheeled mobile robot to which the present invention is applied.

FIG. 4 is an explanatory diagram of an ultrasonic sensor.

FIG. 5 is an explanatory diagram of an ultrasonic sensor.

FIG. 6 is a schematic flowchart of crawling movement.

FIG. 7 is a schematic flowchart of the operation of the leg or the robot body.

FIG. 8 is a flowchart showing a procedure for moving a leg or a robot body in a traveling direction.

FIG. 9 is a flowchart showing a procedure for stable grounding of a leg or a robot body.

FIG. 10 is a flowchart showing a procedure for stable grounding of a leg or a robot body.

FIG. 11 is an explanatory diagram showing a movable range of a leg.

FIG. 12 is an explanatory diagram showing a free leg operation.

FIG. 13 is an explanatory diagram of a farthest contact state of a leg.

FIG. 14 is an explanatory diagram of an operation of a step overstepping pattern according to a conventional method.

FIG. 15 is an explanatory view of an operation of a pattern for moving over a convex portion according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Robot main body 2 Left wheel 3 Left front leg 4,6,8 Wheel 5 Left rear leg 7 Right front leg 9 Right rear leg 10 Ultrasonic sensor 10a Sensor main body 10b Ultrasonic oscillator 10c Ultrasonic receiver 11 Moving object 12 Right moving wheel

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-26174 (JP, A) JP-A-4-10191 (JP, A) JP-A-2-224986 (JP, A) JP-A-3-3 166077 (JP, A) JP-A-62-43371 (JP, A) JP-A-64-78987 (JP, A) JP-A-1-96707 (JP, A) JP-A-62-74774 (JP, A) JP-A-62-241781 (JP, A) JP-A-62-39377 (JP, A) JP-A-61-261170 (JP, A) JP-A-1-106117 (JP, A) JP-A-1-66992 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 57/032 B25J 5/00 B25J 13/08

Claims (1)

(57) [Claims] 1. A robot body comprising a plurality of articulated legs, a ground sensor for detecting that the robot body is grounded is provided on the robot body, and a ground sensor for detecting that the legs are grounded is provided on the legs. The robot body and the leg, or the legged mobile robot equipped with the robot body or the leg, is equipped with an external sensor that determines whether the robot body and the leg can touch the ground by detecting the situation of the surrounding objects. In a crawling mobile robot, in which a leg is moved by repeating a free leg motion in which each leg moves and a standing motion in which each leg lifts and moves while supporting the robot body while each leg is in contact with the ground, The robot body can be stably grounded and moved to the farthest place in the traveling direction. A mobile crawling robot characterized by automatically generating a crawling gait without creating a gait pattern by repeatedly moving and touching a distant place and moving and grounding the legs and the robot body. Gait control method.